Roaring back into multiplexes at age 79 like he’s got something to prove, Ridley Scott has handed down to us the goriest, and what’s more, the largest chapter of the Alien saga yet. The original remains the franchise’s most fastidiously orchestrated work of craft, and James Cameron’s Aliens gave the series its most cathartic action showstoppers. Covenant, to its credit and detriment, is simply the most...